Insights into interoceptive and emotional processing: Lessons from studies on insular HD-tDCS
Miriam Kipping1, Sandra A Mai-Lippold1, Beate M Herbert2,3
1Clinical and Health Psychology, Institute of Psychology and Education, Ulm University, Ulm, Germany.
Psychophysiology
|July 1, 2024
Summary
High-definition transcranial direct current stimulation (HD-tDCS) applied to the right insula did not enhance interoception or emotion in healthy adults. Physical preactivation showed some improvements in interoceptive sensibility, but not from direct brain stimulation.
Area of Science:
- Neuroscience
- Psychophysiology
- Brain Stimulation
Background:
- Interoception, the perception of internal bodily signals, is crucial for emotional experiences and is often impaired in psychiatric disorders.
- The neural underpinnings of interoception and emotion require further elucidation, particularly concerning potential interventions.
- The right anterior insula is a key region implicated in both interoceptive and emotional processing.
Purpose of the Study:
- To investigate the feasibility of enhancing interoception and emotional processing using high-definition transcranial direct current stimulation (HD-tDCS) targeting the right anterior insula.
- To assess the impact of HD-tDCS, with and without physical preactivation, on various dimensions of interoceptive abilities and emotional processing in healthy individuals.
Main Methods:
- Two studies were conducted using a single-blind, cross-over, online design with HD-tDCS applied to the right anterior insula or sham stimulation.
- Study one (N=52) assessed interoceptive sensibility, confidence, accuracy, and emotional evaluation.
- Study two (N=39) incorporated ergometer cycling pre-stimulation to examine effects on interoception and emotion.
Main Results:
- HD-tDCS applied to the right insula did not yield significant improvements in interoceptive dimensions in study one.
- In study two, physical preactivation led to improvements in interoceptive sensibility and confidence over time, independent of sham or insula stimulation.
- No significant enhancement of interoceptive or emotional processing was observed directly attributable to HD-tDCS of the right insula in either study.
Conclusions:
- Targeting the right anterior insula with HD-tDCS does not consistently enhance interoceptive or emotional processing in healthy adults.
- Improvements in interoceptive sensibility observed with physical preactivation may stem from network activation or training effects, not direct insula stimulation.
- Future HD-tDCS research may benefit from targeting broader regions within the interoceptive network rather than isolated structures like the insula.
